• 한국항공운항학회지
• /
• 제19권1호
• /
• pp.24-28
• /
• 2011

This paper reviews a ceiling prediction method based on a mesoscale meteorological modeling system in South Korea. The study was motivated by the tendency of higher model ceiling height than the observed in daily operational forecasts. The goal of the paper is to report an effort to improve the operational ceiling prediction skill by conducting numerical experiments controlling a model parameter. In a case experiment, increasing constant values used in the relationship between extinction coefficients and concentration showed better performance, indicating a short-term strategy for operational local ceiling forecast improvement.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2001년도 제23회 KOSCO SYMPOSIUM 논문집
• /
• pp.35-41
• /
• 2001

A second-order conditional moment closure(CMC) model is applied to the prediction of local extinction in a turbulent hydrocarbon diffusion flame and compared with direct numerical simulation(DNS) results for the flame. Combustion of a hydrocarbon fuel is described by a simple two-step mechanism. A second-order correction for conditional mean reaction rate terms is made by the assumed pdf method. The results show that the second-order closure is necessary for accurate prediction of intermediate species, while first-order CMC gives good predictions for fuel, oxidant, product and temperature. Conditional variances and covariances are well predicted during an extinction process while they are overpredicted during a reignition process.

• International Journal of Internet, Broadcasting and Communication
• /
• 제15권2호
• /
• pp.81-88
• /
• 2023

As a result of this study, the income generation effect generatded by regional universities for the region is KRW 130.6 billion (direct and indirect income effect KRW 90.9 billion, induced income effect KRW 39.6 billion). In addition, it is estimated that the effect of regional universities on inducing employment in the region is 2,145 per year. Unless quality jobs are secured, the outflow of population to the metropolitan area will accelerate, and the disappearance of local areas will emerge as a social problem in the near future. Considering the effect of local universities on the local economy revealed through the results of this study, that is, the income and job creation effects, the government will be able to prevent local extinction by providing bold financial support to local universities. If it is difficult to afford it with government finances alone, it can be solved by opening the door to universities for admission through donations, which many advanced countries are introducing..

• 디지털산업정보학회논문지
• /
• 제20권1호
• /
• pp.149-160
• /
• 2024

This paper was conducted to improve understanding of how the start-up process affects the local community and how young entrepreneurs build and grow their businesses in the process through analysis of young people who started businesses in the region. The research method was conducted through in-depth interviews with 10 young entrepreneurs who started businesses in the western Gyeongsangnam-do region, where population decline is prominent, and the collected data was analyzed through a grounded theory approach to derive common and meaningful themes between each case. proceeded. As a result of the study, insights were derived about the background of entrepreneurs settling in the region, the motivation for starting a business using local resources, the impact of government and local government support, business strategies for sustainable growth, and the entrepreneurs' personal performance. Through this analysis, we hope to provide important insights into the positive impact local entrepreneurship has on the community and how young entrepreneurs contribute to local development.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 1999년도 제19회 KOSCO SYMPOSIUM 논문집
• /
• pp.55-61
• /
• 1999

A convolution algorithm combined with Fourier transformation is applied to the tomographic reconstruction of the asymmetric soot structure to identify the local soot volume fraction distribution. The line of sight integrated data from light extinction measurement with multi-angular scanning form basic information for the deconvolution. Multi-peak following interpolation technique is applied to obtain the effect of increasing number of scanning angles. Measurement of LII signal for the same flame shows the validity of this reconstruction technigue.

• 한국연소학회지
• /
• 제8권3호
• /
• pp.24-30
• /
• 2003

A convolution algorithm combined with Fourier transformation has been applied to the tomographic reconstruction of asymmetric soot structure to identify the local soot volume fraction distribution. Line-of-sight integrated data from light extinction measurement with multi-angular scanning formed basic information for the deconvolution. Multi-peak following interpolation technique was applied to obtain the effect of increasing number of scanning angles. Height-by-height reconstructed soot volume fraction distribution was compared with laser-induced incandescence signals.

• 천문학회보
• /
• 제41권2호
• /
• pp.40.2-40.2
• /
• 2016

The attenuation of starlight by dust in galactic environments is investigated through models of radiative transfer in a spherical, clumpy interstellar medium (ISM). We show that the attenuation curves are primarily determined by the wavelength dependence of absorption rather than by the underlying extinction (absorption+scattering) curve; the observationally derived attenuation curves cannot constrain a unique extinction curve unless the absorption or scattering efficiency is specified. Attenuation curves consistent with the Calzetti curve are found by assuming the silicate-carbonaceous dust model for the Milky Way (MW), but with the $2175{\AA}$ bump suppressed or absent. The discrepancy between our results and previous work that claimed the Small Magellanic Cloud dust to be the origin of the Calzetti curve is ascribed to the difference in adopted albedos; we use the theoretically calculated albedos whereas the previous ones adopted empirically derived albedos from observations of reflection nebulae. It is found that the model attenuation curves calculated with the MW dust are well represented by a modified Calzetti curve with a varying slope and UV bump strength. The strong correlation between the slope and UV bump strength, as found in star-forming galaxies at 0.5 < z < 2.0, is well reproduced if the abundance of the UV bump carriers is assumed to be 30-40% of that of the MW-dust; radiative transfer effects lead to shallower attenuation curves with weaker UV bumps as the ISM is more clumpy and dustier. We also argue that some of local starburst galaxies have a UV bump in their attenuation curves, albeit very weak.

• 한국연소학회지
• /
• 제8권3호
• /
• pp.15-23
• /
• 2003

Partial quenching structure of turbulent diffusion flames in a turbulent mixing layer is investigated by the method of flame hole dynamics in order to develop a prediction model for turbulent flame lift off. The essence of flame hole dynamics is derivation of the random walk mapping, from the flame-edge theory, which governs expansion or contraction of flame holes initially created by local quenching events. The numerical simulation for flame hole dynamics is carried out in two stages. First, a direct numerical simulation is performed for constant-density fuel-air channel mixing layer to obtain the turbulent flow and mixing fields, from which a time series of two dimensional scalar dissipation rate array is extracted at a fixed virtual flame surface horizontally extending from the end of split plate to the downstream. Then, the Lagrangian simulation of the flame hole random walk mapping projected to the scalar dissipation rate array yields temporally evolving turbulent extinction process and its statistics on partial quenching characteristics. The statistical results exhibit that the chance of partial quenching is strongly influenced by the crossover scalar dissipation rate while almost unaffected by the iteration number of the mapping that can be regarded as a flame-edge speed.

• 한국컴퓨터정보학회:학술대회논문집
• /
• 한국컴퓨터정보학회 2023년도 제67차 동계학술대회논문집 31권1호
• /
• pp.161-163
• /
• 2023

본 논문은 K-지방소멸지수를 바탕으로 지역 성장에 초점을 두어 지방소멸 대응 방향성을 제시한다. 연령별 추계인구 데이터와 총 요소 생산성 데이터를 비교하여 청년층의 감소가 지역 성장에 미치는 영향을 보여준다. 이에 따라 연도별 청년이 가장 많이 유출되는 지역을 샘플링하여 전출 사유를 알아보고 지역별 차별화된 대응 방향성을 제시한다.

• 한국물환경학회지
• /
• 제30권5호
• /
• pp.477-485
• /
• 2014

Imha Reservoir is connected to Andong Reservoir via a diversion tunnel allowing water to pass between. The diversion tunnel is equipped with screens to exclude exotic largemouth bass due to their predatory impacts on prey assemblages resulting in a degradation of species richness of local fish fauna and extinction of local fish populations in Korea. Flow pattern changes resulting from the fish screens and trash racks were investigated using a computational fluid dynamics (CFD) model. Numerical simulations showed that the decrease in the discharge capacity of the tunnel is approximately 8.6% and the headloss coefficient for fish screen at Andong intake tower was determined to be 1.5. In order not to allow the small fishes enough to pass through the wire openings enter into Imha Reservoir through tunnel, the velocity in the tunnel should be greater than 1.48 m/s which is a critical ascending velocity of the bass. This study suggests that it can keep the velocity higher enough to exclude largemouth bass when a gate opens with the condition of 1.0m difference in water stage between two reservoirs.